This project has as its basic aim the elucidation of the mechanisms whereby starch is broken down to glucose in the digestive system of mammals. To this end we are purifying, characterizing and studying the substrate specificities of the several individual enzymes of starch digestion of which the actions are so far incompletely understood. Special attention is being paid to the largely unexplored question of how the complex oligosaccharide products of alpha-amylase action, the alpha-limit dextrins, are degraded to glucose. The search for such enzymes has included the pancreas as well as the intestinal mucosa. The special enzymology pertaining to the digestion of raw starch will be explored, together with the metabolic fate of chemically modified starches of the type used in processed foods. Starch will also be examined for non-carbohydrate components that might be covalently bound. In a second part of the project the levels of starch-degrading enzymes in the digestive system of growing animals will be observed as well as the effects on these enzymes in the mature animal of diet, starvation and diabetes. Finally alpha-amylase and alpha-glucosidase levels will be determined in serum and urine from patients suffering from pancreatic disease and other diseases that may cause hyperamylasemia, with a view to developing improved diagnostic assays for pancreatic dysfunction. In these assays we will use information gained from the study of two alpha-glucosidases we have discovered in the pancreas.